Magnetic chuck



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MAGNETIC CHUCK Filed March 2e, 1925 Bday 1,1928.

.Patented May l, 1928.

UNITED 'STATES 'PATENTy OFFICE.

JULIUS BING, O'F EISENACH, GERMANY, ASSIGNOR T0 MIAGNET-WERK G.. M. IB. EISENACH SPEZIALFABRIK FR ELECTROMAGNET APPARATE, 0F EISENACH,

GERMANY.

` Application med March 26, 1925, Serial No My invention relates to improvements in magnetic work holding apparatus and it particularly has reference to round electromagnetic chucks.

The known round magnetic chucks having a surface plate subdivided into a number of fields of different polarity have the great disadvantage, that the separatinggaps between the separate 4pole iields lie very far apart so that onlyv relatively large pieces of work can be attached. The greater the subdivision into dierent poles of the plate, the smaller can the pieces of work be, which are to be mounted on the plate, and the greater can the number of such pieces be. In rectangular chucks, the face plate may be very finey subdivided by laying alternate narrow Strips of brass and iron next to one another and bolting the-strips together. It would be very diiicult to adapt this method ot construction to round chucks as in this case the surface plate would have to consist of sepa-A rate alternate rings of brass and iron, the fitting together of which would necessitate very accurate work and take a considerable amount of time, more particularly as it is important for the rings to lit as closely together as-possible. According to my invention these and other diiiiculties are overcome by the pole plate heing constructed by winding two metal strips, a magnetic and a non-magnetic one, in the form of a spiral. Further features and objects of my invention will more clearly appear from the following specification having reference to the accompanying drawing showing by way of exempliication a pre- :terred embodiment of the principles of my invention. In said drawing 40 Fig. 1 is an axial section and Fig. 2 is a front view of the upper plate of a chuck constructed according to the invention. The chuck shown comprises inthe usual manner a dished magnet part 1 with the winding 2 and the pole plate 3. The latter is made by winding a strip 5 of brass and a strip 6 of iron together in the form of a spiral around a circular core piece 4 made of iron. In order to cause the separate windings to fit as closely together as possible the strips may be wound on under considerable MAGNETIC CHUCK.

.18,584, and in Germany September 27, 1924.

tension and may. if necessary be heated. After they have been wound on, the ends of the strips arefixed, for instance by solder 5r, y

'this way is then placed on the magnet partl in the usual manner and attached to it by screws or the like. 65 Inthe manner described a pole plate of any desired degree of subdivision may be mad ewith a relatively small amount of work and at very small cost.

I claim 70 a 1. A pole plate for magnetic work holdmg apparatus, comprising at least two spirais inserted one within the other of alternate strips of magnetic and non-magnetic metal, 4and a'metal ring surroundingsaid 75 spirals.

2..A pole plate for magnetic chucks, comprising a metal core piece, -a disc-shaped body surrounding said core piece, and being formed of two spirals inserted one Within the other of strips of magnetic and non-magnetic metal, and a closed metal ring surrounding said disc-shaped body.

3. A pole plate for magnetic chucks, comprising a core piece of magnetic metal, an. iron strip spiral surrounding said' core piece l and having its convolutions spaced apart from one another, a non-magnetic metal vstrip spiral disposed within the spaces between the convolutions of said iron strip 9o spn.al,sa1d spirals closely secured one to .the other.

4. A pole plate for magnetic chucks, comprising a core piece of magnetic metal, an iron strip spiral surrounding said core piece and having its convolutions spaced aparti from one another,a brass strip spiral dis-4 posed within the spaces between the convolutions of said -iron strip spiral, said spirals closely secured one to the other, and aclosed 10o iron ring surrounding said spirals.-

In testimony whereof I affix my signature.

JULIUS BING. 

